| Is Missile: | yes |
| R-29RM Shtil/RSM-54 | |
| Type: | SLBM |
| Filling: | The payload (2800 kg) was capable of carrying ten 100 kT yield MIRV warheads, though only a four MIRV warhead version entered production. |
| Yield: | 200 kt each[1] |
| Engine: | Three-stage liquid fueled stages using N2O4/UDMH propellant[2] |
| Guidance: | Astroinertial |
| Accuracy: | CEP 500 metres |
| Length: | 14.8 metres[3] |
| Diameter: | 1.9 m |
| Weight: | 40.3 tonnes |
| Payload Capacity: | 2800 kg |
| Designer: | Makeyev Rocket Design Bureau |
| Manufacturer: | Krasnoyarsk Machine-Building Plant |
| Service: | 1986–2010 |
| Used By: | Soviet Navy Russian Navy |
The R-29RM Shtil[4] (Russian: Штиль, lit. "Calmness", NATO reporting name SS-N-23 Skiff) was a liquid propellant, submarine-launched ballistic missile in use by the Russian Navy. It had the alternate Russian designations RSM-54 and GRAU index 3M27.[5] It was designed to be launched from the Delta IV submarine, each of which is capable of carrying 16 missiles. The R-29RM could carry four 100 kiloton warheads and had a range of about .[6] They were replaced with the newer R-29RMU2 Sineva and later with the enhanced variant R-29RMU2.1 Layner.
Development of the R-29RM started in 1979 at the Makeyev Rocket Design Bureau. The navy accepted the armament in 1986 and subsequently installed the D-9RM launch system consisting of a cluster of 16 R-29RM on board the nuclear-propelled Project 667BDRM submarines.[2]
See main article: Operation Behemoth. On 6 August 1991 at 21:09, K-407, under the command of Captain Second Rank Sergey Yegorov, became the world's only submarine to successfully launch an all-missile salvo, launching 16 R-29RM (RSM-54) ballistic missiles of the total weight of almost 700 tons in 244 seconds (operation code name "Behemoth-2"). All the missile hit their designated targets at the Kura Missile Test Range in Kamchatka.[7]
Several R-29RM were retrofitted as Shtil' carrier rockets to be launched by Delta-class submarines, the submarines being mobile can send a payload directly into a heliosynchronous orbit, notably used by imaging satellites. Outside the confines of the Russian military, this capability has been used commercially to place three out of four microsatellites into a low Earth orbit with one cancellation assigned to the Baikonur Cosmodrome for better financial terms.
The last boat carrying R-29RM, K-51, went into refit to be rearmed with the newer R-29RMU Sineva on 23 August 2010.[8]